US4110546A - DC arc furnace having a rotating arc - Google Patents

DC arc furnace having a rotating arc Download PDF

Info

Publication number
US4110546A
US4110546A US05/739,048 US73904876A US4110546A US 4110546 A US4110546 A US 4110546A US 73904876 A US73904876 A US 73904876A US 4110546 A US4110546 A US 4110546A
Authority
US
United States
Prior art keywords
arc
enclosure
furnace
melt
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/739,048
Other languages
English (en)
Inventor
Sven-Einar Stenkvist
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Norden Holding AB
Original Assignee
ASEA AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ASEA AB filed Critical ASEA AB
Application granted granted Critical
Publication of US4110546A publication Critical patent/US4110546A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • C21C5/5229—Manufacture of steel in electric furnaces in a direct current [DC] electric arc furnace
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • a known DC arc furnace comprises a cylindrical furnace enclosure having a circular hearth for containing a melt, and an arcing electrode centrally positioned in the enclosure above the melt and forming an arc therewith when the electrode and melt are placed in circuit with a source of DC of adequate power.
  • the connections are made so that the melt is anodic and the arcing electrode is cathodic.
  • the melt is obtained by charging the furnace with solid metal pieces such as steel scrap, the charge being melted down to form the melt.
  • the anodic power connection with the melt can be made by a melt contact electrode extending through the hearth and which is laterally offset from the arcing electrode, the electric and magnetic forces involved then causing the arc to deflect angularly in a direction away from the anodic contact electrode.
  • the arc can be made to deflect in different directions by selective connection with one or another of the contact electrodes. With a symmetrical distribution of the contact electrodes and with all of them connected anodically to the DC power source the arc can be vertically directed in alignment with the arcing electrode.
  • the electromagnets which comprise iron cores and electrically powered coils for the cores
  • the magnetic field influencing the arc can be made to rotate with consequent rotation of the arc at an angularity with respect to the arcing electrode.
  • the arc can be made to rotatively sweep through a downwardly flaring conical path.
  • the present inventor has found that when the described type of electric furnace is charged with solid metal pieces, such as steel scrap, for the melt-down phase, that the charge is seldom if ever symmetrically charged around the arcing electrode which is centrally located within the cylindrical furnace enclosure. Therefore, during this melt-down period portions of the furnace wall are shielded from the arc radiation or flare by higher piles of material while portions are exposed by lower portions of material so that the more exposed wall portions receive a greater amount of arc radiation than other portions which are shielded by higher piles of scrap. He has found that such an uneven melt-down action is unfavorable both with regard to the wear on the furnace wall and the rate the melt-down proceeds.
  • the present invention comprises a DC electric arc furnace with a furnace enclosure having a hearth for containing a melt, both being generally cylindrical or circular in cross section.
  • An arcing electrode is positioned centrally in the enclosure above the melt to form an arc with the melt when the electrode and melt are placed in circuit with a source of DC.
  • Magnetic means are provided for forming a rotating magnetic field in the enclosure causing the arc to deflect angularly and to rotate.
  • means are provided for varying the rotative speed of the arc with the rotative speed responsive to the enclosure's temperature at one or a plurality of locations interspaced around the enclosure's periphery.
  • the arrangement is such that the rotative speed of the deflected arc is relatively fast when the arc is deflected towards relatively hot portions of the enclosure and the speed is relatively slow while the arc deflects towards relatively cold portions of the enclosure during each complete rotation of the arc.
  • the rotative speed of the arc slows down, thus putting more heat into the high pile of solid metal being melted down and which is shielding the furnace wall against the arc radiation.
  • the rotative speed of the arc is increased so that the furnace wall no longer shielded by a high pile of material, receives the arc radiation or arc flare for a relatively short period of time.
  • the arc flare radiation is used more effectively for the melt-down and is not wasted by destructive radiation against the furnace wall.
  • FIG. 1 is a vertical section
  • FIG. 2 is a horizontal section, of a DC arc furnace of the type described and embodying the principles of the present invention.
  • FIG. 2a shows the control arrangement for varying the arc rotative speed.
  • an angularly deflected arc is indicated by the arrow 1 formed at the tip of a vertical arcing electrode 2 passed through an opening in the furnace enclosure roof 3, the furnace having the usual pouring spout 4 at one side and at the opposite side and laterally offset from the arcing electrode 2 having a melt contact electrode 5 positioned in an electrode pocket 6 formed in the vertical furnace wall 3a and which receives a portion of the melt M in the hearth 3b of the furnace enclosure.
  • the furnace wall 3a and its hearth 3b are circular in cross section with the arcing electrode 2 centrally positioned.
  • the arc angularity indicated by the arrow 1 is inherently obtained when the DC arc power is connected so that the melt contact electrode 5 is anodic and the arcing electrode 2 is cathodic.
  • the arc can be made to follow a truly vertical path aligned with the arcing electrode 2 if the direct current source 7 carries the positive current to the melt contact electrode 5 by a conductor 8 extending under the bottom of the furnace from a position diametrically opposite to this electrode 5, as disclosed by the Stenkvist application Ser. No. 647,215 filed Jan. 7, 1976, now U.S. Pat. No. 4,038,483, July 26, 1977, and also assigned to the assignee of the present application.
  • the previously referred to electromagnet is positioned below the hearth 3b, which is of non-magnetic construction, and is shown as being a three, four or other multi-pole magnetizing winding or windings or coils 10 and an iron core 11 forming in this instance four symmetrically disposed pole pieces 12 below the furnace bottom, as indicated by FIG. 2.
  • this electromagnet arrangement With supplying this electromagnet arrangement with two-phase low frequency alternating current, such as at a frequency below 25 Hz and preferably from 0.01 to 10 Hz, the arc can by the magnetic forces produced be made to not only deflect as indicated by the arrow 1, but also to follow a circular sweeping path as indicated at 9 in FIG. 2. If the electromagnet has three poles for example, a three-phase AC supply can be used.
  • four temperature measuring devices 13, 14, 15 and 16 are uniformly distributed around the vertical wall of the furnace enclosure and at a level most apt to receive arc radiation of the greatest intensity. These devices may be as disclosed by the Krusenstierna et al U.S. Pat. No. 3,512,413, May 19, 1970, the disclosure of this patent being hereby incorporated into the present application. Similar devices can also or alternatively be placed in the furnace roof 3 as indicated at 17 and 18 in FIG. 1. It is possible to use only one of the devices but normally a multiplicity would be used.
  • each of the devices provides a signal which as schematically indicated by FIG. 2a, is fed to the source of the AC power feed to the various coils of the various pole pieces 12a, 12b 12c and 12d shown in FIG. 2, so as to vary the frequency applied to these coils within the low frequency range previously mentioned.
  • Low frequency AC supply means of controllable variable frequency are commercially available and which operate both rotatively and statically.
  • FIG. 1 illustrates the melt produced by a prior melt-down.
  • solid metal pieces are charged in the hearth 3b to inherently form piles of varying height.
  • the conductor 8 orients the arc vertically.
  • the various coils of the electromagnet are energized with low frequency AC, the arc deflection 1 again becomes angular as shown in FIG. 1 while at the same time rotatively sweeping through the circle 9 shown by FIG. 2.
  • the arrangement is such that if, for example, in FIG. 2 the sensor 13 provides a signal indicating low temperature, its signal controls the AC power source to reduce the frequency so that the rotative speed of the arc slows down. If then, for example, the sensor 14 provides a high temperature reading, the AC power source adjusts to a higher frequency under the control of that sensor 14 so that the arc flare sweeps by this portion of the furnace enclosure wall more rapidly.
  • sensors or transducers are normally required, distributed around the circumference of the furnace wall 3a at a suitable height above the slag line so that any tendency to uneven melt-down or furnace wall temperature is detected quickly.
  • the frequencies used for rotative speed control should preferably be between 0.01 to 10 Hz. As a starting value, 0.25 Hz could be used which might then be changed to 0.5 Hz in the region where the rotative sweep is to be accelerated. It is also possible to use as a starting frequency one that is reduced in the regions where the sensors detect lower temperatures.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)
  • Discharge Heating (AREA)
US05/739,048 1975-11-06 1976-11-05 DC arc furnace having a rotating arc Expired - Lifetime US4110546A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE7512428 1975-11-06
SE7512428A SE396531B (sv) 1975-11-06 1975-11-06 Anordning vid likstromsmatade ljusbagsugnar

Publications (1)

Publication Number Publication Date
US4110546A true US4110546A (en) 1978-08-29

Family

ID=20325992

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/739,048 Expired - Lifetime US4110546A (en) 1975-11-06 1976-11-05 DC arc furnace having a rotating arc

Country Status (6)

Country Link
US (1) US4110546A (enrdf_load_stackoverflow)
JP (2) JPS5260455A (enrdf_load_stackoverflow)
DE (1) DE2648575C2 (enrdf_load_stackoverflow)
FR (1) FR2331233A2 (enrdf_load_stackoverflow)
GB (1) GB1557571A (enrdf_load_stackoverflow)
SE (1) SE396531B (enrdf_load_stackoverflow)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4403328A (en) * 1981-02-26 1983-09-06 Asea Ab DC Arc furnace power connection system
US4425659A (en) 1980-09-17 1984-01-10 Asea Ab Metal oxide reduction furnace
US4495625A (en) * 1983-07-05 1985-01-22 Westinghouse Electric Corp. Magnetic field stabilized transferred arc furnace
US4686687A (en) * 1986-03-04 1987-08-11 Nippon Steel Corporation Anode system for plasma heating usable in a tundish
US5317591A (en) * 1991-06-20 1994-05-31 Asea Brown Boveri Ltd. Direct-current arc furnace
US5956366A (en) * 1997-02-26 1999-09-21 Nkk Steel Engineering, Inc. Arc furnace and method in which molten material is stirred and the arc is guided
US5960027A (en) * 1995-09-19 1999-09-28 Mitsubishi Denki Kabushiki Kaisha Apparatus for controlling arc deflection in an arc furnace
WO2000045980A1 (en) * 1999-02-02 2000-08-10 Singapore Polytechnic Metal casting
US6549557B1 (en) 2001-05-18 2003-04-15 Ucar Carbon Compan, Inc. AC arc furnace with auxiliary electromagnetic coil system for control of arc deflection
US20090232181A1 (en) * 2008-03-14 2009-09-17 Di Carcano Pedro Bianchi Systems and methods for controlling the electrode position in an arc furnace
RU2455599C2 (ru) * 2007-12-18 2012-07-10 Смс Зимаг Аг Устройство и способ получения металла или соединения металла
RU2486717C2 (ru) * 2011-07-12 2013-06-27 Открытое Акционерное Общество "Тяжпрессмаш" Электродуговая печь постоянного тока
CN105571313A (zh) * 2014-11-05 2016-05-11 大同特殊钢株式会社 电弧炉的操作方法
RU2598421C1 (ru) * 2015-04-17 2016-09-27 Открытое Акционерное Общество "Тяжпрессмаш" Электродуговая печь постоянного тока
US9903653B2 (en) 2014-11-05 2018-02-27 Daido Steel Co., Ltd. Melting furnace
US10001324B2 (en) 2014-11-05 2018-06-19 Daido Steel Co., Ltd. Method of operating electric arc furnace
RU182794U1 (ru) * 2017-10-18 2018-09-03 Общество с ограниченной ответственностью "Промышленная группа "Металлургия благородных металлов" Дуговая печь постоянного тока
US10234206B2 (en) 2014-11-05 2019-03-19 Daido Steel Co., Ltd. Electric arc furnace

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4581745A (en) * 1985-01-16 1986-04-08 Timet Electric arc melting apparatus and associated method
JPH0334590U (enrdf_load_stackoverflow) * 1989-08-14 1991-04-04
DE4102554A1 (de) * 1991-01-29 1992-09-03 Dresden Vakuumtech Gmbh Schaltungsanordnung zum zuenden und betreiben einer hohlkatodenbogenentladung
IT1289001B1 (it) * 1996-10-14 1998-09-25 Danieli Off Mecc Sistema per l'agitazione elettromagnetica del metallo liquido in forni elettrici ad arco a corrente continua
JP2010037651A (ja) * 2008-07-10 2010-02-18 Kobe Steel Ltd 真空アーク溶解法によるチタンインゴットの製造方法
IT201800006804A1 (it) 2018-06-29 2019-12-29 Dispositivo di rilevamento del livello di metallo in un forno elettrico ad arco

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1562825A (en) * 1924-11-11 1925-11-24 Evreynoff Georg Electric furnace
US3512413A (en) * 1965-11-26 1970-05-19 Asea Ab Measuring body capable of being built into the wall of a high-temperature furnace
US3683094A (en) * 1971-02-18 1972-08-08 Max P Schlienger Arc positioning system for rotating electrode wheel arc furnace

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2652440A (en) * 1950-07-18 1953-09-15 Battelle Development Corp Electric arc melting furnace
US2849658A (en) * 1953-12-24 1958-08-26 Westinghouse Electric Corp Control apparatus
DE1093926B (de) * 1959-08-05 1960-12-01 Heraeus Gmbh W C Einrichtung zur Ablenkung des Lichtbogens in einem Vakuum-Lichtbogenofen
US3378620A (en) * 1965-03-23 1968-04-16 Union Carbide Corp Electric furnace control
DE1758726A1 (de) * 1968-07-30 1971-03-11 Roechlingsche Eisen & Stahl Lichtbogen-Stahlschmelzofen mit erhoehter Haltbarkeit der Ausmauerung
JPS5118882B1 (enrdf_load_stackoverflow) * 1971-02-02 1976-06-14
FR2188812A5 (en) * 1972-06-09 1974-01-18 Schlienger Max Rotating electrode whell arc furnace - has arc positioning system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1562825A (en) * 1924-11-11 1925-11-24 Evreynoff Georg Electric furnace
US3512413A (en) * 1965-11-26 1970-05-19 Asea Ab Measuring body capable of being built into the wall of a high-temperature furnace
US3683094A (en) * 1971-02-18 1972-08-08 Max P Schlienger Arc positioning system for rotating electrode wheel arc furnace

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4425659A (en) 1980-09-17 1984-01-10 Asea Ab Metal oxide reduction furnace
US4403328A (en) * 1981-02-26 1983-09-06 Asea Ab DC Arc furnace power connection system
US4495625A (en) * 1983-07-05 1985-01-22 Westinghouse Electric Corp. Magnetic field stabilized transferred arc furnace
US4686687A (en) * 1986-03-04 1987-08-11 Nippon Steel Corporation Anode system for plasma heating usable in a tundish
US5317591A (en) * 1991-06-20 1994-05-31 Asea Brown Boveri Ltd. Direct-current arc furnace
US5960027A (en) * 1995-09-19 1999-09-28 Mitsubishi Denki Kabushiki Kaisha Apparatus for controlling arc deflection in an arc furnace
US5956366A (en) * 1997-02-26 1999-09-21 Nkk Steel Engineering, Inc. Arc furnace and method in which molten material is stirred and the arc is guided
WO2000045980A1 (en) * 1999-02-02 2000-08-10 Singapore Polytechnic Metal casting
SG87016A1 (en) * 1999-02-02 2002-03-19 Singapore Polytechnic Metal casting
US6549557B1 (en) 2001-05-18 2003-04-15 Ucar Carbon Compan, Inc. AC arc furnace with auxiliary electromagnetic coil system for control of arc deflection
RU2455599C2 (ru) * 2007-12-18 2012-07-10 Смс Зимаг Аг Устройство и способ получения металла или соединения металла
US20090232181A1 (en) * 2008-03-14 2009-09-17 Di Carcano Pedro Bianchi Systems and methods for controlling the electrode position in an arc furnace
RU2486717C2 (ru) * 2011-07-12 2013-06-27 Открытое Акционерное Общество "Тяжпрессмаш" Электродуговая печь постоянного тока
CN105571313A (zh) * 2014-11-05 2016-05-11 大同特殊钢株式会社 电弧炉的操作方法
US9903653B2 (en) 2014-11-05 2018-02-27 Daido Steel Co., Ltd. Melting furnace
US10001324B2 (en) 2014-11-05 2018-06-19 Daido Steel Co., Ltd. Method of operating electric arc furnace
US10215494B2 (en) * 2014-11-05 2019-02-26 Daido Steel Co., Ltd. Method of operating electric arc furnace
US10234206B2 (en) 2014-11-05 2019-03-19 Daido Steel Co., Ltd. Electric arc furnace
TWI674386B (zh) * 2014-11-05 2019-10-11 日商大同特殊鋼股份有限公司 操作電弧爐之方法
CN105571313B (zh) * 2014-11-05 2020-01-03 大同特殊钢株式会社 电弧炉的操作方法
RU2598421C1 (ru) * 2015-04-17 2016-09-27 Открытое Акционерное Общество "Тяжпрессмаш" Электродуговая печь постоянного тока
RU182794U1 (ru) * 2017-10-18 2018-09-03 Общество с ограниченной ответственностью "Промышленная группа "Металлургия благородных металлов" Дуговая печь постоянного тока

Also Published As

Publication number Publication date
JPS5260455A (en) 1977-05-18
SE7512428L (sv) 1977-05-07
DE2648575A1 (de) 1977-05-18
JPS611990A (ja) 1986-01-07
FR2331233B2 (enrdf_load_stackoverflow) 1983-04-15
SE396531B (sv) 1977-09-19
DE2648575C2 (de) 1984-10-18
JPS6113154B2 (enrdf_load_stackoverflow) 1986-04-11
GB1557571A (en) 1979-12-12
FR2331233A2 (fr) 1977-06-03

Similar Documents

Publication Publication Date Title
US4110546A (en) DC arc furnace having a rotating arc
US2774803A (en) Inductive stirring device for metallurgical furnace
US4149024A (en) Arc furnace for reducing metal oxides and method for operating such a furnace
CA1070743A (en) D.c. arc furnace
US4495625A (en) Magnetic field stabilized transferred arc furnace
US4016355A (en) Device in direct current arc furnaces
JP7345643B2 (ja) 電気アーク炉内における液体金属の撹拌方法
GB2173380A (en) Electric arc melting apparatus and associated method
US3793468A (en) Furnace apparatus utilizing a resultant magnetic field or fields produced by mutual interaction of at least two independently generated magnetic fields and methods of operating an electric arc furnace
US4805186A (en) Process for the continuous melting of scrap in an electric direct-current furnace and electric furnace for carrying out the process
JPS5966684A (ja) とりべ炉を運転する方法
US2144886A (en) Electric furnace
US4034146A (en) Method and apparatus for equalizing the wall lining wear in three phase alternating current electric arc furnaces
US3619467A (en) Electric arc furnace and method of protecting the refractory lining thereof
RU2486717C2 (ru) Электродуговая печь постоянного тока
CN117367098A (zh) 用于金属制造过程的炉组件
RU2040864C1 (ru) Плавильная электрическая печь постоянного тока
US3597519A (en) Magnetic-field rotating-electrode electric arc furnace apparatus and methods
US3749804A (en) Method for determining the depth of immersion of electrodes in a reduction furnace
EP0286934B1 (en) Method of reducing lining wear in a ladle containing a melt
JPS5927185A (ja) 金属の溶解方法とそれに使用するア−ク炉
US2849658A (en) Control apparatus
US3783170A (en) Electric arc furnace apparatus having a shaped magnetic field for increasing the utilized area of the arcing surface of an electrode and improving the heating efficiency
GB953800A (en) Improvements in or relating to vacuum electric arc furnaces
GB1506020A (en) Direct current arc furnace